a rectangle is 12 cm long and 9 cm wide. Its perimeter is doubled when each of its sides is increased by a fixed length. what is the length?

length = 12 cm

breadth = 9 cm.

perimeter of rectangle = 2( l+b)

= 2(12+9) = 2(21) = 42cm.

New length = (12+x) cm

New breath = (9+x) cm

2(12+x+9+x) = 42×2

2(21+x) = 84

21+ x = 84/2

21+x = 42

x= 42-21= 21

x= 21.

Therefore, length = (12+x)cm

=( 12+21) cm = 33cm.

Explanation:

Firstly we have written the length and breadth of the rectangle.

And the perimeter of rectangle i.e. 2(l+b)

Then, as it is in question we have doubled the perimeter

And at last, we have got the value of x.

and by putting the value in the new length we will get our answer.

hope you have got your answer dear.

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